Krakatoa, East of Java

"Craven Walker didn't envision the lamps as paragons of grooviness. 'They weren't marketed like that—they were almost staid,' Granger says. Indeed, an ad in a 1968 edition of the American Bar Association Journal touted the 'executive' model—mounted on a walnut base alongside a ballpoint pen.
"As light fixtures go, the lamps are peculiar in that they don't cast much light. They appeal to people at ease in darkness."

Abigail Tucker in a 2013 Smithsonian article explains the history of the lava lamp.